Cover photograph (Copyright © 2002, American Society for Microbiology. All Rights Reserved.): Protein expression of Rhizobium etli wild-type and aniA mutant strains. The inactivation of aniA in R. etli causes a pronounced alteration in carbon flux regulation and a drastic decrease in global protein expression. R. etli CE3-specific proteins are shown in red, blue spots show proteins from the aniA mutant strain, and green spots indicate proteins present in both strains. (See related article on page 2287.)